trunk/rdesktop/licence.c

/*
   rdesktop: A Remote Desktop Protocol client.
   RDP licensing negotiation
   Copyright (C) Matthew Chapman 1999-2000
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "rdesktop.h"
#include "crypto/rc4.h"

extern char username[16];
extern char hostname[16];
extern BOOL licence;

static uint8 licence_key[16];
static uint8 licence_sign_key[16];

/* Generate a session key and RC4 keys, given client and server randoms */
void
licence_generate_keys(uint8 *client_key, uint8 *server_key, uint8 *client_rsa)
{
        uint8 session_key[48];
        uint8 temp_hash[48];

        /* Generate session key - two rounds of sec_hash_48 */
        sec_hash_48(temp_hash, client_rsa, client_key, server_key, 65);
        sec_hash_48(session_key, temp_hash, server_key, client_key, 65);

        /* Store first 16 bytes of session key, for generating signatures */
        memcpy(licence_sign_key, session_key, 16);

        /* Generate RC4 key */
        sec_hash_16(licence_key, &session_key[16], client_key, server_key);
}

/* Send a licence request packet */
static void
licence_send_request(uint8 *client_random, uint8 *rsa_data,
                     char *user, char *host)
{
        uint32 sec_flags = SEC_LICENCE_NEG;
        uint16 userlen = strlen(user) + 1;
        uint16 hostlen = strlen(host) + 1;
        uint16 length = 120 + userlen + hostlen;
        STREAM s;

        s = sec_init(sec_flags, length + 2);

        out_uint16_le(s, LICENCE_TAG_REQUEST);
        out_uint16_le(s, length);

        out_uint32_le(s, 1);
        out_uint32_le(s, 0xff010000);

        out_uint8p(s, client_random, SEC_RANDOM_SIZE);
        out_uint16(s, 0);
        out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE));
        out_uint8p(s, rsa_data, SEC_MODULUS_SIZE);
        out_uint8s(s, SEC_PADDING_SIZE);

        out_uint16(s, LICENCE_TAG_USER);
        out_uint16(s, userlen);
        out_uint8p(s, user, userlen);

        out_uint16(s, LICENCE_TAG_HOST);
        out_uint16(s, hostlen);
        out_uint8p(s, host, hostlen);

        s_mark_end(s);
        sec_send(s, sec_flags);
}

/* Process a licence demand packet */
static void
licence_process_demand(STREAM s)
{
        uint8 null_data[SEC_MODULUS_SIZE];
        uint8 *server_random;

        /* Retrieve the server random from the incoming packet */
        in_uint8p(s, server_random, SEC_RANDOM_SIZE);

        /* We currently use null client keys. This is a bit naughty but, hey,
           the security of licence negotiation isn't exactly paramount. */
        memset(null_data, 0, sizeof(null_data));
        licence_generate_keys(null_data, server_random, null_data);

        /* Send a certificate request back to the server */
        licence_send_request(null_data, null_data, username, hostname);
}

/* Send an authentication response packet */
static void
licence_send_authresp(uint8 *token, uint8 *crypt_hwid, uint8 *signature)
{
        uint32 sec_flags = SEC_LICENCE_NEG;
        uint16 length = 58;
        STREAM s;

        s = sec_init(sec_flags, length + 2);

        out_uint16_le(s, LICENCE_TAG_AUTHRESP);
        out_uint16_le(s, length);

        out_uint16_le(s, 1);
        out_uint16_le(s, LICENCE_TOKEN_SIZE);
        out_uint8p(s, token, LICENCE_TOKEN_SIZE);

        out_uint16_le(s, 1);
        out_uint16_le(s, LICENCE_HWID_SIZE);
        out_uint8p(s, crypt_hwid, LICENCE_HWID_SIZE);

        out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE);

        s_mark_end(s);
        sec_send(s, sec_flags);
}

/* Parse an authentication request packet */
static BOOL
licence_parse_authreq(STREAM s, uint8 **token, uint8 **signature)
{
        uint16 tokenlen;

        in_uint8s(s, 6);        /* unknown: f8 3d 15 00 04 f6 */

        in_uint16_le(s, tokenlen);
        if (tokenlen != LICENCE_TOKEN_SIZE)
        {
                ERROR("token len %d\n", tokenlen);
                return False;
        }

        in_uint8p(s, *token, tokenlen);
        in_uint8p(s, *signature, LICENCE_SIGNATURE_SIZE);

        return s_check_end(s);
}

/* Process an authentication request packet */
static void
licence_process_authreq(STREAM s)
{
        uint8 *in_token, *in_sig;
        uint8 out_token[LICENCE_TOKEN_SIZE],
                decrypt_token[LICENCE_TOKEN_SIZE];
        uint8 hwid[LICENCE_HWID_SIZE], crypt_hwid[LICENCE_HWID_SIZE];
        uint8 sealed_buffer[LICENCE_TOKEN_SIZE + LICENCE_HWID_SIZE];
        uint8 out_sig[LICENCE_SIGNATURE_SIZE];
        RC4_KEY crypt_key;

        /* Parse incoming packet and save the encrypted token */
        licence_parse_authreq(s, &in_token, &in_sig);
        memcpy(out_token, in_token, LICENCE_TOKEN_SIZE);

        /* Decrypt the token. It should read TEST in Unicode. */
        RC4_set_key(&crypt_key, 16, licence_key);
        RC4(&crypt_key, LICENCE_TOKEN_SIZE, in_token, decrypt_token);

        /* Construct HWID */
        buf_out_uint32(hwid, 2);
        strncpy(hwid + 4, hostname, LICENCE_HWID_SIZE - 4);

        /* Generate a signature for a buffer of token and HWID */
        memcpy(sealed_buffer, decrypt_token, LICENCE_TOKEN_SIZE);
        memcpy(sealed_buffer + LICENCE_TOKEN_SIZE, hwid, LICENCE_HWID_SIZE);
        sec_sign(out_sig, licence_sign_key, 16,
                 sealed_buffer, sizeof(sealed_buffer));

        /* Deliberately break signature if licencing disabled */
        if (!licence)
                memset(out_sig, 0, sizeof(out_sig));

        /* Now encrypt the HWID */
        RC4_set_key(&crypt_key, 16, licence_key);
        RC4(&crypt_key, LICENCE_HWID_SIZE, hwid, crypt_hwid);

        licence_send_authresp(out_token, crypt_hwid, out_sig);
}

/* Process an licence issue packet */
static void
licence_process_issue(STREAM s)
{
        RC4_KEY crypt_key;
        uint32 length;
        uint16 check;

        in_uint8s(s, 2);        /* 3d 45 - unknown */
        in_uint16_le(s, length);
        if (!s_check_rem(s, length))
                return;

        RC4_set_key(&crypt_key, 16, licence_key);
        RC4(&crypt_key, length, s->p, s->p);

        in_uint16(s, check);
        if (check != 0)
                return;

        /* We should save the licence here */
        STATUS("Server issued licence.\n");
}

/* Process a licence packet */
void
licence_process(STREAM s)
{
        uint16 tag;

        in_uint16_le(s, tag);
        in_uint8s(s, 2);        /* length */

        switch (tag)
        {
                case LICENCE_TAG_DEMAND:
                        licence_process_demand(s);
                        break;

                case LICENCE_TAG_AUTHREQ:
                        licence_process_authreq(s);
                        break;

                case LICENCE_TAG_ISSUE:
                        licence_process_issue(s);
                        break;

                case LICENCE_TAG_RESULT:
                        break;

                default:
                        NOTIMP("licence tag 0x%x\n", tag);
        }
}
1	matty	10	/*
2			rdesktop: A Remote Desktop Protocol client.
3			RDP licensing negotiation
4			Copyright (C) Matthew Chapman 1999-2000
5
6			This program is free software; you can redistribute it and/or modify
7			it under the terms of the GNU General Public License as published by
8			the Free Software Foundation; either version 2 of the License, or
9			(at your option) any later version.
10
11			This program is distributed in the hope that it will be useful,
12			but WITHOUT ANY WARRANTY; without even the implied warranty of
13			MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14			GNU General Public License for more details.
15
16			You should have received a copy of the GNU General Public License
17			along with this program; if not, write to the Free Software
18			Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19			*/
20
21			#include "rdesktop.h"
22			#include "crypto/rc4.h"
23
24			extern char username[16];
25			extern char hostname[16];
26			extern BOOL licence;
27
28			static uint8 licence_key[16];
29			static uint8 licence_sign_key[16];
30
31			/* Generate a session key and RC4 keys, given client and server randoms */
32	matty	25	void
33			licence_generate_keys(uint8 client_key, uint8 server_key, uint8 *client_rsa)
34	matty	10	{
35			uint8 session_key[48];
36			uint8 temp_hash[48];
37
38			/* Generate session key - two rounds of sec_hash_48 */
39	matty	24	sec_hash_48(temp_hash, client_rsa, client_key, server_key, 65);
40			sec_hash_48(session_key, temp_hash, server_key, client_key, 65);
41	matty	10
42			/* Store first 16 bytes of session key, for generating signatures */
43	matty	24	memcpy(licence_sign_key, session_key, 16);
44	matty	10
45			/* Generate RC4 key */
46			sec_hash_16(licence_key, &session_key[16], client_key, server_key);
47			}
48
49			/* Send a licence request packet */
50	matty	25	static void
51			licence_send_request(uint8 client_random, uint8 rsa_data,
52			char user, char host)
53	matty	10	{
54			uint32 sec_flags = SEC_LICENCE_NEG;
55			uint16 userlen = strlen(user) + 1;
56			uint16 hostlen = strlen(host) + 1;
57			uint16 length = 120 + userlen + hostlen;
58			STREAM s;
59
60			s = sec_init(sec_flags, length + 2);
61
62			out_uint16_le(s, LICENCE_TAG_REQUEST);
63			out_uint16_le(s, length);
64
65			out_uint32_le(s, 1);
66			out_uint32_le(s, 0xff010000);
67
68			out_uint8p(s, client_random, SEC_RANDOM_SIZE);
69			out_uint16(s, 0);
70			out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE));
71			out_uint8p(s, rsa_data, SEC_MODULUS_SIZE);
72			out_uint8s(s, SEC_PADDING_SIZE);
73
74			out_uint16(s, LICENCE_TAG_USER);
75			out_uint16(s, userlen);
76			out_uint8p(s, user, userlen);
77
78			out_uint16(s, LICENCE_TAG_HOST);
79			out_uint16(s, hostlen);
80			out_uint8p(s, host, hostlen);
81
82			s_mark_end(s);
83			sec_send(s, sec_flags);
84			}
85
86			/* Process a licence demand packet */
87	matty	25	static void
88			licence_process_demand(STREAM s)
89	matty	10	{
90			uint8 null_data[SEC_MODULUS_SIZE];
91			uint8 *server_random;
92
93			/* Retrieve the server random from the incoming packet */
94			in_uint8p(s, server_random, SEC_RANDOM_SIZE);
95
96			/* We currently use null client keys. This is a bit naughty but, hey,
97			the security of licence negotiation isn't exactly paramount. */
98			memset(null_data, 0, sizeof(null_data));
99			licence_generate_keys(null_data, server_random, null_data);
100
101			/* Send a certificate request back to the server */
102			licence_send_request(null_data, null_data, username, hostname);
103			}
104
105			/* Send an authentication response packet */
106	matty	25	static void
107			licence_send_authresp(uint8 token, uint8 crypt_hwid, uint8 *signature)
108	matty	10	{
109			uint32 sec_flags = SEC_LICENCE_NEG;
110			uint16 length = 58;
111			STREAM s;
112
113			s = sec_init(sec_flags, length + 2);
114
115			out_uint16_le(s, LICENCE_TAG_AUTHRESP);
116			out_uint16_le(s, length);
117
118			out_uint16_le(s, 1);
119			out_uint16_le(s, LICENCE_TOKEN_SIZE);
120			out_uint8p(s, token, LICENCE_TOKEN_SIZE);
121
122			out_uint16_le(s, 1);
123			out_uint16_le(s, LICENCE_HWID_SIZE);
124			out_uint8p(s, crypt_hwid, LICENCE_HWID_SIZE);
125
126			out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE);
127
128			s_mark_end(s);
129			sec_send(s, sec_flags);
130			}
131
132			/* Parse an authentication request packet */
133	matty	25	static BOOL
134			licence_parse_authreq(STREAM s, uint8 token, uint8 signature)
135	matty	10	{
136			uint16 tokenlen;
137
138	matty	24	in_uint8s(s, 6); /* unknown: f8 3d 15 00 04 f6 */
139	matty	10
140			in_uint16_le(s, tokenlen);
141			if (tokenlen != LICENCE_TOKEN_SIZE)
142			{
143			ERROR("token len %d\n", tokenlen);
144			return False;
145			}
146
147			in_uint8p(s, *token, tokenlen);
148			in_uint8p(s, *signature, LICENCE_SIGNATURE_SIZE);
149
150			return s_check_end(s);
151			}
152
153			/* Process an authentication request packet */
154	matty	25	static void
155			licence_process_authreq(STREAM s)
156	matty	10	{
157			uint8 in_token, in_sig;
158	matty	24	uint8 out_token[LICENCE_TOKEN_SIZE],
159			decrypt_token[LICENCE_TOKEN_SIZE];
160	matty	10	uint8 hwid[LICENCE_HWID_SIZE], crypt_hwid[LICENCE_HWID_SIZE];
161			uint8 sealed_buffer[LICENCE_TOKEN_SIZE + LICENCE_HWID_SIZE];
162			uint8 out_sig[LICENCE_SIGNATURE_SIZE];
163			RC4_KEY crypt_key;
164
165			/* Parse incoming packet and save the encrypted token */
166			licence_parse_authreq(s, &in_token, &in_sig);
167			memcpy(out_token, in_token, LICENCE_TOKEN_SIZE);
168
169			/* Decrypt the token. It should read TEST in Unicode. */
170			RC4_set_key(&crypt_key, 16, licence_key);
171			RC4(&crypt_key, LICENCE_TOKEN_SIZE, in_token, decrypt_token);
172
173			/* Construct HWID */
174			buf_out_uint32(hwid, 2);
175			strncpy(hwid + 4, hostname, LICENCE_HWID_SIZE - 4);
176
177			/* Generate a signature for a buffer of token and HWID */
178			memcpy(sealed_buffer, decrypt_token, LICENCE_TOKEN_SIZE);
179			memcpy(sealed_buffer + LICENCE_TOKEN_SIZE, hwid, LICENCE_HWID_SIZE);
180			sec_sign(out_sig, licence_sign_key, 16,
181	matty	24	sealed_buffer, sizeof(sealed_buffer));
182	matty	10
183			/* Deliberately break signature if licencing disabled */
184			if (!licence)
185			memset(out_sig, 0, sizeof(out_sig));
186
187			/* Now encrypt the HWID */
188			RC4_set_key(&crypt_key, 16, licence_key);
189			RC4(&crypt_key, LICENCE_HWID_SIZE, hwid, crypt_hwid);
190
191			licence_send_authresp(out_token, crypt_hwid, out_sig);
192			}
193
194			/* Process an licence issue packet */
195	matty	25	static void
196			licence_process_issue(STREAM s)
197	matty	10	{
198			RC4_KEY crypt_key;
199			uint32 length;
200			uint16 check;
201
202	matty	24	in_uint8s(s, 2); /* 3d 45 - unknown */
203	matty	10	in_uint16_le(s, length);
204			if (!s_check_rem(s, length))
205			return;
206
207			RC4_set_key(&crypt_key, 16, licence_key);
208			RC4(&crypt_key, length, s->p, s->p);
209
210			in_uint16(s, check);
211			if (check != 0)
212			return;
213
214			/* We should save the licence here */
215			STATUS("Server issued licence.\n");
216			}
217
218			/* Process a licence packet */
219	matty	25	void
220			licence_process(STREAM s)
221	matty	10	{
222			uint16 tag;
223
224			in_uint16_le(s, tag);
225	matty	24	in_uint8s(s, 2); /* length */
226	matty	10
227			switch (tag)
228			{
229			case LICENCE_TAG_DEMAND:
230			licence_process_demand(s);
231			break;
232
233			case LICENCE_TAG_AUTHREQ:
234			licence_process_authreq(s);
235			break;
236
237			case LICENCE_TAG_ISSUE:
238			licence_process_issue(s);
239			break;
240
241			case LICENCE_TAG_RESULT:
242			break;
243
244			default:
245			NOTIMP("licence tag 0x%x\n", tag);
246			}
247			}